Compared with the conventional LCD, the organic light emitting display device is a self-luminous display device. Since it does not require a backlight, it possesses the advantages of thinness, power saving, fast response, etc., and also possesses excellent viewing angle and contrast. In general, an organic light emitting display device comprises an array substrate and an OLED light emitting device disposed above the array substrate. The OLED light emitting device includes an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode; wherein, the anode, the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, and the electron injection layer are formed as an OLED semiconductor layer.
According to the light emitting direction, the organic light emitting display device includes a top emission type, a bottom emission type, and a dual emission type. In the top emission type, the organic light emitting display device emits light in the opposite direction to the array substrate provided with sub pixels, and the structure can meet the aperture ratio requirement of a large scale high-resolution OLED panel, so it is often applied to the large scale high-resolution OLED panel. However, since the cathode of the OLED light emitting device on the organic light emitting display device has a high resistivity, a severe voltage drop phenomenon occurs, and once the organic light emitting display device is electrified, non-uniformity in brightness or in image quality occurs.
As shown in FIG. 1, in order to overcome the foregoing problems, an inverted trapezoidal leg a is usually formed around the pixel electrode 1111′ of the array substrate 1′. By controlling the size of the inverted trapezoidal leg a, and controlling the size of the cavity of the pixel definition layer 2′ corresponding to the recessed hole 21′ above the metal connection electrode 1112′ of the array substrate 1′ and the tilt angle formed by the cavity sidewall and the horizontal plane of the array substrate 1′, the cathode 4′ on the OLED semiconductor layer 3′ can enter into the cavity of the recessed hole 21′ above the metal connection electrode 1112′, and is connected to the auxiliary electrode 122′ of the array substrate 1′ with the metal connection electrode 1112′ to reduce the resistance of the cathode 4′ for realizing the objective of reducing the voltage drop. However, the inventors have found that the pixel definition layer 2 and the inverted trapezoidal legs a of the organic light emitting display device in the foregoing method need to be developed by double exposure to form a positive inverted trapezoidal structure, which is not only complicated but also requires time and labor.